Field of the Invention
The present invention relates to a workpiece cutting method of cutting a platelike workpiece such as a semiconductor wafer by using a cutting blade.
Description of the Related Art
A cutting apparatus including a cutting blade is used in dividing a semiconductor wafer having a plurality of semiconductor devices formed on the front side, an optical device wafer having a plurality of optical devices formed on the front side, or any platelike workpiece such as a glass substrate, ceramics substrate, and resin substrate having a plurality of devices formed on the front side to thereby obtain a plurality of individual chips. The cutting blade included in the cutting apparatus has a cutting edge, which is formed by fixing abrasive grains of diamond or the like with a plating or by fixing the abrasive grains with a bond such as metal and resin. Self-sharpening of the cutting edge is accelerated by cutting a workpiece with the cutting edge to thereby maintain constant sharpness. Cutting of the workpiece is effected by crumbling the workpiece with the abrasive grains of the cutting edge.
Thus, the cutting is effected by the crumbling, so that chipping is generated on both sides of a cut groove formed on the workpiece by using the cutting blade. If the chipping has a size extending beyond the division line where the cut groove is formed on the workpiece, defective devices may be produced. Accordingly, the cut groove is suitably imaged and observed during the operation of cutting the workpiece to inspect the size of the chipping (see Japanese Patent Laid-open No. 2009-246015, for example).
Such observation of the cut groove is called kerf inspection, wherein the size of the chipping is measured. If the size of the chipping falls out of tolerance, an error message is displayed and an operator can visually recognize the condition of the cut groove (kerf) formed on the workpiece (e.g. wafer). When it is determined that the chipping does not reach the devices, the devices are adopted as usable products, whereas when it is determined that the chipping reaches the devices, any step is taken, for example, a step of removing any unusable portion from the workpiece is taken. Furthermore, the cutting blade causing the generation of the chipping is replaced.